Its one of two moments and they both generally snowball into other moments which snowball into other moments, which ultimately ruin the experience for me. Basically a few glaring problems starts revealing cracks in the other parts of the story. I ignore some of the graphical limitations but it doesn't change the initial problem of Sephy being that short sighted, despite his arrogance he's not a complete idiot which is what this scene really tells me. Sephiroth is one of the few villains who is actually known for his intelligence in the series and this scene only says he's an idiot and kinda dispels this myth about him.

This is why I prefer the LO version as it makes more sense and I feel it still let's Cloud have his heroic moments but not at the expense of making Sephy look like a complete fool.

YouTube - Crisis Core: C09S08 Goodbye Sephiroth [English Sub]

Above is a variation of the scene as seen in Crisis Core which is a bit more faithful to the original including the immersion destroying part...

On topic though, I would like to point out that looking at Sephy's body mechanics in his fight with Zack, he actually does move towards using both hands to reinforce his attacks which is more than he ever did for Cloud. He even deflects Cloud's attack one handed while being badly injured. Also, for fun and "lulz", look carefully at the scene where Cloud stabs Sephiroth and it becomes apparent that Cloud literally cut him in half from the waist.